let arr = [1, 2, 3];
Array.prototype.addValue = function(i, v) {
  let newValue = this.splice(0);
  newValue.splice(i, 0, v);
  return newValue;
};
console.log(arr, "arr");
let arr2 = arr.addValue(2, 6);
console.log(arr2, "arr2");
